[zimeg]

Summary

This pull request adds a url_source element example that matches the URL source element docs payloads.

• UrlSource.java builds example01() as a single UrlSourceElement and example02() as a task card block with two URL sources, mirroring the Python and JS examples.
• UrlSourceTest.java asserts the serialized JSON for both examples.
• README entry under Block elements.

The docs page frontmatter still reads "Displays a URL source with optional icon.", left over from before icon_url was removed. The Javadoc and README use "Displays a URL source for referencing within a task card block." to match the Python and JS examples.

Testing

1. Run mvn test -Dtest=elements.UrlSourceTest in block-kit.
2. Optionally post UrlSource.example02() with chat.postMessage and confirm both sources render as links on the task card.

🤖 Generated with Claude Code

[mwbrooks]

✅ Thanks @zimeg, the tests pin both docs payloads exactly, which makes this one easy to trust.

[mwbrooks]

suggestion (non-blocking): Since icon_url is gone, could we update the summary in the docs page frontmatter too? Then this Javadoc, the README, and the Python and JS examples all match the docs again, the way AGENTS.md asks.

[zimeg]

📚 thanks @mwbrooks, agreed! the docs page summary is the source of truth, so we'll fix it there and drop the stale icon mention. the new summary matches what this Javadoc, the README line, and the Python and JS examples already say:

Displays a URL source for referencing within a task card block.

so once that lands, everything matches the docs again with no example changes needed.